This invention is directed to polyacrylate esters with ammonium salt groups as well as to their use as cationic surfactants, particularly as active ingredients of metal adjuvants.
Ammonium salts of organic amines have long been used as cationic wetting agents and emulsifiers. They can be used in the textile industry as antistatic agents and to improve the handle of textiles, and in yarn preparations to improve slippage capabilities and processing characteristics, such as sewing properties. Ammonium salts of organic amines are used for selective oleophilization in the flotation of salts, such as alkali salts, and of ores, such as zinc ores. They can act as corrosion protection agents in suitable systems and are used as metal adjuvants, for example for the preparation of drilling and cutting fluids and as surface active materials for the moistening of wet metal surfaces. Ammonium salts of selected organic compounds are suitable as adhesives in road construction and for grinding and flushing pigments.
Polymeric compounds which contain a majority of the ammonium salt groups linked in a lateral position in comb-like fashion are of particular interest, since these compounds can be adapted optimally to the intended application with respect to the solubility and the number of ammonium groups in the polymeric molecule.
Suitable polymeric compounds in which ammonium salt groups can be linked laterally include the polyacrylate esters. These can be obtained by the copolymerization of acrylate esters and acrylate ester derivatives with tertiary amino groups, which are converted into the ammonium salts after the polymerization. In addition, further monomers, such as styrene, methyl, ethyl, butyl, and dodecyl (meth)acrylate, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, acrylamide and acrylonitrile can be copolymerized.
The free radical copolymerization of the aforementioned monomers results in polymers with a very broad distribution of molecular weights. Accordingly, the molecular weight distribution curve is flat and moreover has two or more maxima, which indicate that the polymerization product is relatively heterogeneous. It may be assumed that the reason for this lies in copolymerization parameters of the individual monomers, which deviate appreciably from the ratio of 1, and is caused, in particular, by the content of tertiary or quaternary nitrogen in the comonomers.
It has been ascertained that such polymers obtained by copolymerization contain portions which are physiologically hazardous and may also have toxic properties. It is suspected that these undesirable properties may be attributed to the low molecular weight portions of the polymer. The removal of these portions from the polymer is not possible in an economic manner. For many applications, the physiological safety of products is an absolute prerequisite for their usability. It is therefore of particular interest to synthesize polyacrylate esters with quaternary ammonium groups which are free of physiologically hazardous components.
The use of an anionic polymerization method, such as that described in the German Offenlegungsschrift 22 62 588, for the synthesis of acrylate polymers with a molecular weight of 500 to 5,000 does not represent a useful solution to the aforementioned task. The danger of gelling the reaction products is high. Moreover, the transfer of an anionic polymerization method to an industrial scale is also rather problematic for safety reasons.